On a used high milage older type engine in moderate temps it's hardly
going matter much, IMO.
15W40 would be fine.
or 15W50
or even 20W50.
I like 15W50 a lot and run it in my better engines.
It's not like this is say, a  2007 or later modern engine with only 40K
on it, requiring thin oil.

On 3/25/2013 10:51 AM, neil n wrote:
> This is re: my '81 Vanagon with Jetta 2.0 swap. Hope to get out
> camping soon. Will be in cooler PNW climes possibly traveling into CA
> warmer climes.
>
> Maybe I should run 10W-40 during this currently cooler to subsequent
> warmer season?
>
> Was running 15W-40 year round but rarely drive the van in temps cooler
> than 0� C.
>
> The web shows use of multi viscosity oils up to 40W for this 2.0 in a
> Jetta, but since this engine works harder in a Vanagon and may see
> higher oil temps, maybe I should use a *w-50 oil?
>
> Bad idea?
>
> Neil.
>
> On Wed, Mar 13, 2013 at 9:51 PM, Dennis Haynes <d23haynes57@hotmail.com> wrote:
>
>> You would be amazed the engine damage that can occur from the wrong oil viscosity in cold weather. Even on non VWs. Modern engines can usually start no matter what now. Have oil that is too thick and all sorts of stuff happens. My favorite is crank and cam seals actually getting pushed out. Hondas and Toyotas. BTDT.
>
>